Fracture Mechanics and Surface Chemistry Studies of Fatigue Crack Growth in an Aluminum Alloy.

摘要

Fracture mechanics and surface chemistry studies were carried out to develop further understanding of the influence of water vapor on fatigue crack growth in aluminum alloys. The room temperature fatigue crack growth response was determined for 2219-T851 aluminum alloy exposed to water vapor at presures from 1 Pa to 30 Pa over a range of stress intensity factors (K). Data were also obtained in vacuum and dehumidified argon. The test results showed that, at a frequency of 5 Hz, the rate of crack growth is essentially unaffected by water vapor until a threshold pressure is reached. Above this threshold, the rates increased, reaching a maximum within one order of magnitude increase in vapor pressure. (Author)